release/src-rt-6.x.4708/linux/linux-2.6.36/arch/xtensa/mm/mmu.c

   1 /*
   2  * xtensa mmu stuff
   3  *
   4  * Extracted from init.c
   5  */
   6 #include <linux/percpu.h>
   7 #include <linux/init.h>
   8 #include <linux/string.h>
   9 #include <linux/slab.h>
  10 #include <linux/cache.h>
  11
  12 #include <asm/tlb.h>
  13 #include <asm/tlbflush.h>
  14 #include <asm/mmu_context.h>
  15 #include <asm/page.h>
  16
  17 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  18
  19 void __init paging_init(void)
  20 {
  21         memset(swapper_pg_dir, 0, PAGE_SIZE);
  22 }
  23
  24 /*
  25  * Flush the mmu and reset associated register to default values.
  26  */
  27 void __init init_mmu(void)
  28 {
  29         /* Writing zeros to the <t>TLBCFG special registers ensure
  30          * that valid values exist in the register.  For existing
  31          * PGSZID<w> fields, zero selects the first element of the
  32          * page-size array.  For nonexistent PGSZID<w> fields, zero is
  33          * the best value to write.  Also, when changing PGSZID<w>
  34          * fields, the corresponding TLB must be flushed.
  35          */
  36         set_itlbcfg_register(0);
  37         set_dtlbcfg_register(0);
  38         flush_tlb_all();
  39
  40         /* Set rasid register to a known value. */
  41
  42         set_rasid_register(ASID_USER_FIRST);
  43
  44         /* Set PTEVADDR special register to the start of the page
  45          * table, which is in kernel mappable space (ie. not
  46          * statically mapped).  This register's value is undefined on
  47          * reset.
  48          */
  49         set_ptevaddr_register(PGTABLE_START);
  50 }
  51
  52 struct kmem_cache *pgtable_cache __read_mostly;
  53
  54 static void pgd_ctor(void *addr)
  55 {
  56         pte_t *ptep = (pte_t *)addr;
  57         int i;
  58
  59         for (i = 0; i < 1024; i++, ptep++)
  60                 pte_clear(NULL, 0, ptep);
  61
  62 }
  63
  64 void __init pgtable_cache_init(void)
  65 {
  66         pgtable_cache = kmem_cache_create("pgd",
  67                         PAGE_SIZE, PAGE_SIZE,
  68                         SLAB_HWCACHE_ALIGN,
  69                         pgd_ctor);
  70 }